This is an application for a K24 mentoring award for patient-oriented research (POR) from Anne Cappola, MD, ScM, and Associate Professor of Medicine at the Perelman School of Medicine at the University of Pennsylvania (Penn). The candidate has a strong record of mentorship, leadership, and research productivity. Her research program encompasses translational and POR studies at the intersection of endocrinology and geriatrics. The scientific goal of this proposal is to investigate the physiologi underpinnings and clinical ramifications of subclinical hypothyroidism in the elderly. The candidate's NIA-funded R01 grant, plus two new aims examining the adaptability of the thyroid axis to aging, will form the basis for the training plan of the grant. Additional research opportunities are available in the candidate's other ongoing NIH-funded studies. The mentoring goals of this application are to engage and support the training of Penn fellows and junior faculty to conduct POR in aging. The career development goal of this application is to support the candidate's professional development and program building in clinical investigation. This will be achieved through engaging in sustained training experiences with two national experts, convening a local retreat on aging research, developing a training grant for POR in aging, and improving the national network of POR research in hormones and human aging. The institutional environment for clinical and translational science at Penn is outstanding, and the proposal integrates multiple programs from Penn's CTSA. The Department of Medicine at Penn has made a substantial commitment, including protected time and dedicated space, toward the candidate's sustained success as a patient-oriented researcher responsible for training a new generation of junior investigators who conduct research in older participants.